Option B
Gwen is in 24th floor
<em><u>Solution:</u></em>
Given that to get the 1st, 3rd 5th, or 7th floors, you use elevator bank a
To get to the 2nd , 4th , 6th or 8th floors , you use elevator Bank b
From this we see that,
To reach odd numbered floors, we use elevator Bank a
To reach even numbered floors, we use elevator Bank b
<em><u>If Gwen uses elevator bank b to reach her office which floor is she on ?</u></em>
So if she uses elevator bank b, she must reach even numbered floor
From given options, 23rd floor, 41st floor and 35th floor are odd numbered floor
But option B 24th floor is a even number
So she will reach 24 th floor
